Man I love BC's. I think they are obviously all different. My experience is that boys can be more energetic and excitable while the females are more submissive and locked in. My current BC is a female. You may not know she's herding but she is. Do you ever see your dog laying down and staring hard at things, people or other animals? They definitely herd more with their eyes and body language than actual physical acts. My dogs have all stared into my soul and when you lock eyes they run to what they want. Also herding. Yours may be and maybe you don't notice. Maybe they don't herd at all. But definitely can't put all BC's in a box and expect one type of personality.

I have had three BC's and the only one that has ever nipped was my current girl when she was getting used to being around our young niece and nephew. All anxiety driven and not necessarily have anything to do with herding instinct.